Many people were surprised by a comment by Dr. Robert Redfield, the director of the Centers for Disease Control and Prevention, in an interview for “CBS This Morning,” during which he said that acute flaccid myelitis:

“doesn’t appear to be transmissible from human to human.”

Wait, then how do kids get it?

Is Acute Flaccid Myelitis Contagious?

Since we don’t actually know what causes AFM, it is certainly possible, although rather unlikely, that it is caused by something that is not communicable.

But remember, the leading theory is that AFM is caused by an enteroviral infection, either EV-D68 and EV-A71, as most kids develop symptoms shortly after they had viral symptoms, and these two viruses are most commonly identified.

And you are typically contagious when you are sick with an enteroviral infection.

So how can the CDC Director say that AFM “doesn’t appear to be transmissible from human to human?”

It is because even if the virus that causes AFM is communicable, you can’t actually catch AFM from someone.

While the polio virus itself is communicable, paralytic polio isn’t. You can’t catch paralytic polio. Instead, you can catch polio, and then you have the small chance that it develops into paralytic polio.

It may not sound like a big difference, but it is.

Just consider what might happen if AFM itself was contagious, and if most of the kids who were exposed to someone with AFM developed AFM themselves…

We would likely see a lot more cases of AFM, especially in clusters in homes, daycare centers, and schools.

Instead, most cases seem to be isolated.

AFM Clusters

But aren’t there reports of clusters of AFM?

“In September 2016, an acute care hospital in Arizona notified the Maricopa County Department of Public Health (MCDPH) of a suspected case of AFM and subsequent cluster of 11 children who were evaluated with similar neurologic deficits; differential diagnoses included transverse myelitis and AFM.”

Notes from the Field: Cluster of Acute Flaccid Myelitis in Five Pediatric Patients — Maricopa County, Arizona, 2016

Yes, kind of.

But they aren’t clusters of epidemiological linked cases.

In Arizona, for example, only four of the 11 children were confirmed to have AFM and “no epidemiologic links were detected among the four patients.”

“In October 2016, Seattle Children’s Hospital notified the Washington State Department of Health (DOH) and CDC of a cluster of acute onset of limb weakness in children aged ≤14 years.”

Similarly, at Seattle Children’s Hospital, the ten cases in their “cluster” had nothing in common, except for having prodromal respiratory or gastrointestinal symptoms about seven days before developing AFM symptoms.

It is likely that you see “clusters” at some hospitals simply because they are referral hospitals for a large region.

But even if we don’t know why some kids with these viral infections develop paralysis and other don’t, if they are the cause, then you wouldn’t develop AFM if you never actually had the virus.

“While we don’t know if it is effective in preventing AFM, washing your hands often with soap and water is one of the best ways to avoid getting sick and spreading germs to other people.”

About Acute Flaccid Myelitis

So handwashing and avoiding others who are sick is still the best strategy to try and avoid getting AFM.